1. Technical Field
The present disclosure relates to a light emitting device, an image display device, and an electronic apparatus.
2. Description of the Related Art
A liquid crystal display device is an image display device that does not have a light emitting function, and is used integrally with a light emitting device that irradiates a liquid crystal panel serving as a display screen with light. Examples of the light emitting device include an edge-light type light emitting device in which a light source is placed at an edge portion of a light guide plate that is provided on the back surface of a liquid crystal panel, and a direct-type light emitting device in which a light source is placed on the back surface or the front surface of a liquid crystal panel. The examples of the light emitting device further include a backlight-type light emitting device that irradiates a transmissive liquid crystal panel with light from the back surface thereof, and a front-light type light emitting device that irradiates a reflective liquid crystal panel with light from the front surface thereof.
When the light emitting device emits light, a light source generates radiant heat. By the radiant heat of the light source, the temperature of a liquid crystal panel may rise, and whereby the display quality may be degraded and electronic devices may give out due to overheating. Hence, there has been an invention of a light emitting device in which the temperature of a light source is measured by providing a thermistor on the light emitting device and measuring the resistance value of the thermistor (see Japanese Patent Application Laid-open No. 2009-199745). When a rise in temperature of the light source is high, the luminance of the light emitting device is lowered so as to suppress the rise in temperature of a liquid crystal panel. In other words, the thermistor has a function of derating the light emitting device (making it operate at a lower than rated value) with respect to the temperature.
When a thermistor is installed in a light emitting device, the thermistor is bonded to a base or the like of the light emitting device, for example. Due to variation with time and changes in temperature, however, there may be a case in which the bonding of the thermistor to the base comes off and the thermistor is separated and lifted from the base. If the thermistor is lifted from the base, the resistance value of the thermistor changes, and the detection value of the thermistor fluctuates. Consequently, the thermistor may not be able to derate the light emitting device appropriately with respect to the temperature. While the process control has been performed conventionally so as to prevent the lifting of the thermistor, the yield may be deteriorated.
For the foregoing reasons, there is a need for a light emitting device, an image display device, and an electronic apparatus that can suppress the change in detection value of a thermistor when the lifting of the thermistor arises.